The present invention generally relates to air pollution control and, more particularly, is concerned with a temperature-controlled exhaust particulate collection system for use with a high-temperature material processing facility, for example, a furnace typically used in an industrial foundry.
In many industries, and particularly those which employ high-temperature material processing facilities, such as furnaces and incinerators, there exists the problem of removing suspended solid particulates from the flow of exhaust gases which is to be vented to the atmosphere. Clean air standards are mandating the removal of these particulates from the vented gases to reduce pollution of the atmosphere.
It has become conventional practice to employ some type of particulate filtration and collection system with such high-temperature facilities to remove the solid pollutants from the flue or exhaust gases. Representative of systems found in the prior art are the ones disclosed in U.S. Pat. No. (2,840,454) to Tomlinson et al, Webster et al (U.S. Pat. No. 2,871,987), Wyrough (U.S. Pat. No. 3,568,415), Greenspan (U.S. Pat. No. 3,608,278), Ikeda et al (U.S. Pat. No. 3,767,536), Gardenier (U.S. Pat. No. 3,782,074), Ostby et al (U.S. Pat. No. 3,948,623), Cold et al (U.S. Pat. No. 4,110,088), Schaltenbrand (U.S. Pat. No. 4,157,901), Fattinger et al (U.S. Pat. No. 4,251,236), Johnson, Jr. (U.S. Pat. No. 4,289,511), Skiven et al (U.S. Pat. No. 4,314,830) and Ando et al (U.S. Pat. No. 4,642,127).
As shown in the above-cited prior art, it is also conventional practice to use a serial arrangement of various types of devices to filter and collect the suspended particulates from the gaseous flow before venting it to the atmosphere. For example, Webster et al disclose a system for removing solids from waste gases which has a quench tower connected to the outlet of a reactor, and a precipitator, cyclone separator and bag filter serially connected downstream from the quench tower.
Further, in those systems where bag filters are used, some means is typically provided for cleaning them. Johnson, Jr., Schaltenbrand and Wyrough disclose devices having a series of nozzles for supplying pressurized air to the interiors of the bags to dislodge collected particulate material from the exteriors thereof. Other cleaning devices are known which shake the bags to dislodge particulate material collected on the interiors thereof.
From the above-cited prior art, it can be deduced that an extensive amount of development effort has gone into particulate filtration and collection systems for the purpose of reducing air pollution by industrial material processing facilities. However, a system approaching optimum has yet been deviced and many current systems have major drawbacks in their reliability and temperature controls. Consequently, a need still exists for improvements in particulate collection system design to eliminate these drawbacks.